1. Field of Invention
The present invention relates to locks, and more particularly to a lock enhancing device which is arranged to reinforce the strength of conventional locks so as to prevent them from being easily damaged, thus failure to provide sound security.
2. Description of Related Arts
A wide variety of locks have been widely used for security purposes. A conventional door lock which is incorporated in a door usually comprises an actuation unit which has a key slot formed therein, a knob assembly comprising an outer protective housing and an inner knob frame attached on an outer and an inner side of a door panel respectively wherein the actuation unit is mounted in the outer protective housing in a rotatably movable manner, and a locking latch mounted between the outer protective housing and the inner knob frame in such a manner that the actuation unit, upon being inserted with a predetermined key, is adapted to drive the locking latch to engage with a door frame by which the door is pivotally supported so that the door panel is locked with respect to the door frame. Conversely, the actuation unit is also adapted to drive the locking latch to disengage with the door frame so that the door panel can be unlocked with respect to the door frame.
As a matter of fact, notwithstanding its popularity, such a conventional door lock has several observable discrepancies. First of all, the very function of the outer protective housing is to protect and strengthen the actuation unit so as to prevent it from being easily damaged or destroyed by an unauthorized trespasser. Unfortunately, very often, the outer protective housing is not strong enough both in terms of the materials used and its structure so that an intentional trespasser, by strongly twisting the actuation unit or vigorously breaking the outer protective housing, can be able to destroy the door lock and open the door. Even though the outer protective housing is not broken altogether by the external force, such a substantial impact may have caused considerable distortion to it which then becomes extremely vulnerable to future damages.
Second, the connection between the outer protective housing and the inner knob frames is usually not strong enough so that when a trespasser applies vigorous impact to the door lock, the connection between the first and the inner knob frame will be broken altogether and, as a result, the outer protective housing and the inner knob frame and the actuation unit may detach from the door and leave the door unlocked immediately.
Moreover, the connection between the outer protective housing and the inner knob frames is usually accomplished by the virtue of a plurality of connecting screws. However, usually, such connecting screws can be screwed from the inner knob frame, such that when the door lock is mounted on a glass door, an intentional trespasser may easily break the glass and then put his/her hands inside the room for screwing out the connecting screws from inside the glass door. As a result, the door lock is easily detached from the glass door, leaving the room unprotected.
Because of the important objective which a door lock has to achieve, governments in various territories have adopted different standards regulating the sales and quality of locks available in that territory. Among those standards and regulations, in United States of America, ANSI/BHMAA156.5-2001 categorizes an anti-twist ability and an impact resistance of a regular door lock as each having three distinct levels, the median of which are 160 Nm and 100 J respectively. As can be seen from these figures, there exist a very high official standard expected from a qualify door lock, and in respect of this, most conventional door locks fail to achieve the required standard.
Because of the inherent structural features of conventional door locks as mentioned above, a stronger and more secure lock is definitely required.